A 20-ounce cup was $2.89 at my local Arby's. You can also get it in a value-size, but I was told it would be just the syrup and shake base without the other accouterments.
The shake had a good consistency: smooth without being too thick or thin.
The flavor was mostly like chocolate syrup (the same stuff you use to make chocolate milk) with hints of mint. There's that sweet syrupiness to it, especially when you get some of the chocolate swirl.
The Andes Mints are all on top, but give a really good pop of chocolate and refreshingly cool mint when you manage to get one. I'd recommend mixing them in for a richer chocolate and mint experience.
Overall, Arby's Mint Chocolate Swirl Shake is nice enough, but I'd like more chocolate and less chocolate syrup to the taste and a stronger mint flavor.
Nutritional Info - Arby's Mint Chocolate Swirl Shake - 20 oz (517g)
Calories - 750 (from Fat - 230)
Fat - 26g (Saturated Fat - 18g)
Sodium - 450mg
Carbs - 119g (Sugar - 99g)
Protein - 16g